Opel Diplomat: the V8 Opel that took on Mercedes-Benz

The Opel Diplomat was Opel’s flagship from 1964 to 1977 and the top model of the KAD range, which it shared with the Kapitän and Admiral. In most respects the three were badge-engineered versions of one car, but only the Diplomat came with a Chevrolet V8.

Opel Diplomat at a glance

Based on one source, the English Wikipedia article on the Opel Diplomat.

History of the Opel Diplomat

A new flagship for 1964

In February 1964 Opel introduced a new range of flagship models as successors to the Kapitän P-LV of 1959–1963. The KAD cars — Kapitän, Admiral and Diplomat, which Opel called “The Big Three” — came with 2.6 and 2.8-litre in-line sixes of 100 or 125 PS, or with the Chevrolet small-block 283 V8 of 4.6 litres and 190 PS, coupled to a two-speed Powerglide automatic. From October 1966 the saloon used the larger 5.4-litre Chevrolet 327 with 230 PS, and as the range-topping model the Diplomat was sold only with a V8.

The Karmann coupé

Between 1965 and 1967 Opel also offered a Diplomat Coupé, built by the coachbuilder Karmann with the 327 engine only. It cost DM 25,500, as much as seven Volkswagen Beetles, and just 347 were made. In styling it owed more than a little to the 1965 Chevrolet Chevelle Malibu Sport Coupé. In September 1967 the Diplomat and its cheaper siblings received rub strips along the flanks, a new ZF recirculating-ball steering and a heated rear window. These cars were even larger than their predecessors, close to 200 inches long, and found little favour with European buyers: between February 1964 and November 1968 Opel built 89,277 KAD cars — 24,249 Kapitäns, 55,876 Admirals and 9,152 Diplomats — against 145,618 of the Kapitän P-LV over a comparable period.

Diplomat B

In March 1969 a new KAD line arrived with new bodies and a more sophisticated chassis with a De Dion rear axle, slightly smaller than before. The Diplomat came either with a fuel-injected 2.8 six, as the Diplomat E, or with the Chevrolet 327 V8, now driving through a three-speed Turbo-Hydramatic. The body was pure General Motors and closely resembled the Holden Brougham from Australia; there was never a right-hand-drive version for Britain, nor a Vauxhall equivalent. From May 1973 Opel offered a long-wheelbase V8 to answer the Mercedes-Benz SEL models. Standard equipment in October 1971 included H1 halogen headlamps, a radio aerial built into the windscreen and a remote-controlled door mirror, and in September 1972 a revised grille moved the OPEL script to the centre.

Even so, the Diplomat struggled against Mercedes-Benz, BMW and Audi. Only 61,559 KAD cars were built between March 1969 and late 1977, of which 4,976 were Kapitäns, about 33,000 Admirals and about 23,500 Diplomats. In 1978 the Senator and Monza replaced the range. The Diplomat’s chassis and V8 also served as the technical base for the Bitter CD sports coupé, and the name came back in the early 1990s as a luxury trim level on the Vectra and Omega.

Design and features

• Chevrolet V8: 4.6 then 5.4 litres, with 190 then 230 PS, in a German luxury saloon.
• KAD family: Diplomat, Admiral and Kapitän were the same car in different trim and engines.
• Karmann coupé: 347 hand-built two-doors at DM 25,500 each.
• De Dion rear axle: a more sophisticated chassis for the second generation from 1969.

Opel Diplomat versions

• Diplomat A (1964): V8 flagship with the Chevrolet 283, then the 327.
• Diplomat Coupé (1965–1967): Karmann-built, 327 engine only.
• Diplomat B (1969): new body and De Dion axle.
• Diplomat E: fuel-injected 2.8-litre six instead of the V8.
• Long-wheelbase V8 (1973): the answer to the Mercedes-Benz SEL.

The Diplomat shared its body and range with the Admiral and the Kapitän, and was replaced by the Senator. More cars are in the Opel collection.

Sources

• Opel Diplomat, English Wikipedia: engines, versions, prices, production figures